Base for electric lamps or similar devices



Sept. 25, 1945. J. J. MALLOY BASE FOR ELECTRIC LAMPS OR SIMILAR DEVICES Filed July 21, 1943 lnven tor John J. MaLLO His A't'iror'neg.

Patented Sept. 25, 1945 BASE FOR ELECTRIC DEVI LAMPS OR SIMILAR CES John J. Malloy, Cleveland Heights, Ohio, assignor to General Electric Com New York pany, a corporation of Application July 21, 1943, Serial No. 495,790

Claims.

My invention relates to electric incandescent lamps and similar devices comprising a bulb having an electrical energy translation element or filament sealed therein and a base on said bulb. More particularly, my invention relates to a base structure for such devices.

One 01' the most common forms of base construction in use at present on electric incandescent lamps coniprisesa threaded metal shell, usually of-brass, having a glass insulator button fastened to one end thereof and a metal end contact or eyelet (likewise usually of brass) secured to the said button and insulated thereby from the metal shell. Inasmuch as the base of a lamp is usually discarded along with the other parts thereof upon bum-out of, or other damage to the lamp, the metal 01' the base shell and eyelet is accordingly wasted upon discarding the lamp.

One object of my invention is to provide a screw-thread base arrangement for electric incandescentdamps and similar devices which is simple and economical in construction and which utilizes a minimum amount of metal.

A feature of the invention is the use of a metal strip or band which is spun or wound into the form of a screw-thread on the neck 01' the-bulb or on a cup-shaped glass bodyattached to the bulb neck, the bulb neck or the glass body preferably being provided with a screw-thread molded on the cylindrical exterior surface thereof and over which the metal strip is spun or wound to form a screw-thread side .contact for the lamp.

Further objects and advantages of my invention will appear from the following description of species thereof and from the accompanying drawing in which:

Fig. 1 is a partial longitudinal sectional view, on an enlarged scale, of a portion of an electric incandescent lamp provided with a base structure comprising my invention; Fig.2 is an elevation of the portion of the lamp shown in Fig. 1; Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 1; Fig. 4 is a transverse section taken on the line H of Fig. 1; Fig. 5 is a perspective detail view of the metal screwthread conductor element of the base shown in Figs. 1-4; Fig. 6 is a longitudinal section on the line 66 of Fig. 7 of a modified form of base construction comprising my invention; and Fig. 7 is a transverse section on the line 1-1 of Fig. 6.

Referring to Fig. 1, the lamp there shown comprises a glass bulb I0 provided with a cylindrical neck portion II, the said neck portion being of reduced diameter so as to form a shoulder I2 on the bulb. ,Sealed within the bulb i0 is a conventional filament mount structure comprising a re-entrant stem l3, an exhaust tube I4, a pair of lead-in wires I5, l6, and an electric energy translation element or filament (not shown) connected to the inner ends of the leadin wires I5, I6 and sealed with the bulb I0.

Secured to the neck II of the bulb is a base structure I1 according to the invention. The said base comprises a molded cup-shaped body II of insulating material, such as glass, having a cylindrical side wall portion I9 and a buttonshaped end wall portion 20. The side wall I9 of the glass body I8 is so shaped as to fit snugly around the neck II or the bulb with the rim 2I of the side wall I 9 abutting or fitting against the shoulder I2 on the bulb- The base I1 may be secured to the neck ll of the bulb by means of a plurality of locking keys or pins 22 which extend through apertures 23 in the cylindrical side wall I9 of the glass body I! and are formed with internal heads 24 which flt into corresponding shallow dish-shaped depressions 25 in the neck II of the bulb. Two of such locking keys 22 are. preferably employed, the said keys being located at diametrically opposite points on the glass body Ill. The keys 22 are made of a readily fusible metal such as solder, and are formed by inserting the solder under pressure, while in a molten state, into the apertures 23 in the glass body I8 so as to 110W into and completely fill the said apertures as well as the shallow depressions 25 in the bulb neck ll.

The cylindrical side wall portion I 9 of the glass body I8 is provided with an external screwthread formed in part by conductor means in the form of a narrow metal strip or band 26, of brass or other suitable non-corrosive metal, which is disposed in a helix on the outer surface 21 of the cylindrical wall I9 of the glass body I8. As shown in Fig. 1, the metal strip 26 is of arcuate cross-section to form the top or convex portions of the screw-threads. The valley or trough portions of the screw-thread is formed by the outer surface 21 of the cylindrical wall I! itself. The helical metal strip 26 is of sufilcient length to form at least one, and preferably one and one-half complete threads.

To lock the helical metal strip 26 against rotation on the cylindrical wall I9, the opposite ends of the strip are suitably secured or anchored to the said wall. For this purpose, the metal strip 26 is provided with inwardly bent tongues 28, 29 at its opposite ends, which tongues extend through suitable apertures in the wall I9 and are bent back around the inner surface 30 of the said wall, as indicated at 3| in Figs. 3 and 4. Preferably, the tongue 28 at that end of the metal'strip 2G nearest the rim 2| of the glass body I8 extends through one of the apertures 23 for the solder keys 22 and is firmly held in place in the said aperture by the solder key therein, while the tongue 29 at the other end of the metal strip 26 posite ends of solder disposed in a recess The said strip 3'! other modifications extends through a slit-shaped aperture 32 (Fig.

2) in the wall l9 of the'glass body. F 7

To provide a firm support for the metal strip 26 and prevent displacement thereof longitudinally of the cylindrical wall cal ridge or screw-thread 33 molded on the outer wall 19 and over which 1 surface 21 of the said the said strip fits tightly. The fixation of the opthe metal strip 26 to the glass body 18 by the tongues 28, 29 holds the strip in place against rotation on the helical positioning ridge 33. Instead of employing a ridge 33 of continuous form, the positioning means for the metal strip 26 may be constituted by a plurality of disposed in helical formaspaced protuberances 1 tion around the cylindrical wall IQ of the glass body IS. The metal strip 26 may be applied to the molded screw-thread 33 either by spinning or wrapping it therearound, or by screw-thread 33. p

The metal strip 28, in addition to serving as a screw-thread for securing the lamp in a socket, also serves as the side contact for the lamp. For this purpose, one lead-in wire I! of the lamp is suitably connected to erably by embedding the said lead-in wire in that solder key 22 which contacts the tongue 28 of the metal strip 26. The other lead-in'wire I6 is preforming it 1 into screw-thread shape and then slipping'it over the end of the bulb neck into place on the molded themetal strip 28,-prefconnected to a suitable bottom or center contact V 34 preferably in the form of asmall button of of the buttoneshaped endwall 20 of the glass body I8. v through an aperture 36 inthe said'end wall 20 of the glass body and is embedded in the solder contact 34;

The modification from the previousform of the inventionin that the glass body l8.is eliminated and the helical metal strip or band 31 mounted instead directly on the bulb neck I l which, for such purpose, may be provided with a molded screw-thread 38 over which the metal strip 31 is applied, as before. issecured against rotation on the molded screw-thread 38 by bending its opposite ends inwardly and back upon themselves to form tongues 39, 40 which extend into and are locked within undercut depressions or recesses 4|, 42 in the cylindrical wall of the bulb neck l I. Leading-inwire I5 is suitably connected to the metal strip 31, preferably to that end of the strip nearest the end of the bulb neck H. For this purpose, the end wall of the bulb may beformed with an outer groove or channel 43 which extends to the recess 42 and through which the lead-in Wire I5 extends into the recess 42 where it is suitably secured, as by soldering,to the tongue 40 of the metal strip 31. The'other leading-in wire I6 is connected to a suitablerbottom or'end contact 48 on an insulating (preferably glass) button .45 cemented' or otherwise attached to the end of the bulb neck. As shown, the end contact M'may be in the form of a metal eyelet l6 fastened to the insulator button and 'to whichthe leading-in wire I6 is soldered. WhileI have shown and described the preforms of my invention, it is obvious that are Possible within the scope ferred 35 in the outer surface The said lead-in wire l6 extends shown in Figs. 6-7 differs thereof. Thus, instead of mechanically attaching the base I! (Figs. 1-5) to the bulb neck ll by means of the solder keys 22, it may be secured to the bulb neck by conventional basing cement.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrical device comprising a bulb having a neck portion and a base mounted on said neck portion and comprising a molded body of insulating material having a cylindrical wall portion surrounding the bulb neck, said bulb' neck having a plurality of depressions therein and the cylindrical base wall having a. plurality of openings opposite said depressions, a plurality of locking keys of easily fusible metal filling the said depressions and openings in said bulb neck and base wall tosecure the base to the bulb neck, conductor means wound around and secured to the said wall portion and arranged to define a helix for engagement with the screw-threads of a socket, one end of said conductor 'means being embedded and anchored in one of'said locking keys, and a leading-in wire embedded in the said one locking key and electrically connected thereby to the said conductormeans. i

2. An electric lampbase comprising a cylindrical wall portion of helical screwthread of at least one full tum formed on its outer surface, and contact means consisting of a helically formed narrow metal 40 consisting of ahelically formed narrow metal band of at least one full'tum conforming to'the pitch of said screw thread and being curved'in cross-section in conformity with the crest of said screw thread, said band being wrapped around the crest of said screw thread and having inwardly bent ends anchored in cavities in said wall portion.

4. .An electric lamp base comprising a cylindrical wall portion of insulating material with a helical screw thread of approximately one and a half turns formed on its outer surface, tact means consisting of a helically formed narrow metal band of approximately one and a half turns conforming to the pitch of said screw thread and wrapped around the surface thereof, said band having inwardly bent ends anchored in cavities in said wall portion.

5. An electric lamp comprising having lead-in wires extending therefrom, and a base portion of insulating material having a helical screw thread of at least one full turn formed 7 on its outer. surface,

and contact means consisting of a helically formed narrow metal band of at least one full turn conforming to the pitch of said screw thread and wrapped around the surface thereof, said band having inwardly bent ends anchored in cavities in said base portion, one of said lead-in wires extending into one .-of said cavities and being soldered therein to an end of said band. 7

' JOHN J. MALLOY.

insulating material with a and cona sealed bulb 

